The present invention relates to an electromagnetically actuatable three-way/two-position directional control valve for alternatively connecting an outlet port to a first or to a second inlet port. The connection is achieved by way of a valve chamber with which the outlet port is in direct communication. The inlet ports each communicate with the valve chamber through sealing seats adapted to be closed or opened by means of a movable valve closure member. An electromagnet is provided for whose housing accommodates a magnet coil and a slidably disposed armature which is actuated when the electromagnet is excited which actuates the valve closure member by way of a valve-actuating tappet. A connection is established between the second inlet port and the outlet port in the inactive position of the valve closure member.
Heretofore, reliable operation of such a three-way/two-position directional control valve required ports of comparatively large cross-sections. Further in prior valves, the valve closure member is actuated by means of a pivotably supported actuating lever for actuating the armature or the valve-actuating tappet.
One shortcoming of such prior three-way/two-position directional control valves which is particularly evident when used as a change-over valve of a vacuum-assisted anti-lock brake system, is that they experience major vacuum leakage during change-over because the two inlet ports and the outlet port are interconnected for a short time during movement of the valve closure member. As a consequence thereof, the vacuum volume requirements are increased and the pressure change-over function is considerably impaired.